Peristaltic pumps, of the type wherein a plurality of roller elements move along the inner race of a cylindrical or semi-cylindrical stator casing in order to pump a fluid through a compressible plastic tube, having the requisite resiliency or memory, by means of intermittent compression and expansion reactions generated within the tube, are of course well known. One such conventional peristaltic pump is disclosed, for example, in U.S. Pat. No. 3,756,752 issued to Stenner. While the operability of the Stenner type pump has apparently proven to be quite satisfactory, the procedure required for operably inserting the compressible pump tube into the pumping chamber has proven to be difficult and tedious. This is due to the fact that the pumping chamber is essentially closed with the exception of a notch formed within a rotatable disk covering the pumping chamber. In order to insert the compressible pump tube within the pumping chamber, one end of the tube is initially disposed within the notch of the cover disk, and the disk is subsequently rotated so as to in effect feed or thread the tube about the rollers disposed within the pumping chamber.
Within blood cell separator systems, it has also proven necessary to sometimes employ pumping mechanisms which can simultaneously pump different fluids, at different volume flow rates, through separate tubes disposed within the pumping chamber. A conventional system of this type is exemplified by U.S. Pat. No. 3,060,348 issued to Della Bianca. As disclosed within such patent, the two compressible pump tubes are operatively associated with stepped pump roller elements. While the means for mounting or inserting the pump tubes within the pump chamber is not apparently disclosed in the Della Bianca patent, it has been attempted to utilize a multi-tube system, such as that shown in the Della Bianca patent, within a pumping system such as that disclosed within the Stenner patent. Such an adaptation, however, has proven extremely difficult to accomplish due to the fact that both tubes have to be simultaneously or separately fed into the pump chamber through the disk notch system of Stenner. In addition, it is also quite difficult and tedious to properly seat the pump tubes upon the roller elements as shown in the Della Bianca patent in order to assuredly accomplish the requisite pumping of both fluids. Still further, it is also necessary to be able to adjust the relative volume flow rates defined within the pump tubes such that, for example, the volume flow rate within one of the tubes has a value which is a predetermined ratio of the volume flow rate within the other tube. The aforenoted prior art does not provide such an adjustment means.
From the foregoing, it will be appreciated that in order to facilitate the mounting or insertion of the pump tubes within the pump chambers of peristaltic pumps, particularly in those instances wherein multi-tube systems are to be employed, it is virtually mandatory that the pump chambers be partially open or have means which render the same openable. In this manner, the requisite accessibility to the pump chambers is able to be established.
In U.S. Pat. No. 3,836,287 issued to Grosholz et al., there is disclosed peristaltic pump apparatus wherein the interior portion of the pump chamber is rendered accessible so as to facilitate the insertion or loading of the pump tube. This procedure is accomplished as a result of the provision of a pivotable cover or lid having integrally movable therewith an arcuate guide element which operatively cooperates with the pump rollers. The lid and guide element system, however, further comprises a relatively complex spring-biased plunger mechanism for properly positioning the roller guide element when the same is moved between its open and closed positions through means of a compound movement which includes both pivotable and translational modes. In addition, separate fastening or securing means must also be provided for securing the cover or lid of the pump mechanism to the pump base when the lid is in its closed position.